DC-DC & charging

It takes the roughly 14.0-14.1V a plain alternator puts out and converts it into the correct staged charging profile your house battery actually needs. Without it, a straight alternator connection chronically undercharges the house bank of batteries if it is the predominant charger.

No - that's the alternator-voltage trap. ~14.0-14.1V is fine for the starter battery it was designed for, but different chemistries and deep-cycle types need different, often higher, staged voltages. That is the whole reason DC-DC chargers exist.

$399 incl GST, and it's in stock. It charges your 12V house battery from either the starter battery/alternator or a solar panel, only drawing from the starter above 13.0V so your vehicle always has power to start.

No, over-speccing is a common "future-proofing" mistake. A standard vehicle alternator can burn out from being under a constant 40-50A load, something it was never designed to do, so on a stock alternator we usually recommend the 20A unit.

Three lead-acid settings (bulk/absorption/float) plus a LiFePO4 setting; input range 13-16V from the alternator and 16-25V from a solar panel.

Yes, it accepts either source, so a van can charge both while driving and while parked in the sun from the one unit.

For a lithium bank we use units like the Ultipower 12V 50A lithium smart charger; one customer charging 3×310Ah lithium in parallel went that route. And we have lithium chargers in 24v and 48v as well.

For Lead acid types a range is C20 to C5, that means charging at 5% to 20%of the bank's amp-hour capacity as charge amps respectively is a good rule. For Lead carbon types a typical range is C20 to C3, that means charging at 5% to 33 %of the bank's amp-hour capacity as charge amps respectively is a good rule; tell us the bank size and we'll match it.

Yes, a proper multi-stage charger will either drops to float and maintains the battery, which is ideal for stored vehicles and standby banks or simply switch off after charging is complete.

A converter just changes voltage (e.g. 24V→12V) to run a circuit; a charger applies a staged charging profile to safely fill a battery. Don't use a plain converter to charge a battery, it wont charge your battery fully and you can break the converter.

Yes, customers use these in boats, trucks, cars and motorhomes to run a 12V circuit off a higher-voltage bank; we also do step-up (12V→24V/48V) units.

No, ours has input low-voltage cut-off (12.8V on 12V) so it stops drawing from your starter battery before the starter goes flat.

Yes, but remember the alternator's spare capacity is limited - the DC-DC takes its share and the battery buffers the rest, there is no problem as long as you have not over specced your DC-DC charger. A 20A size charger is always safe to use in any vehicle if you don't know about the alternator, larger capacity DC-DC chargers are safe to use if you know that the alternator is of high capacity, such as some off-road vehicles come with an increased amp-rated alternator. And also sometimes people have fitted aftermarket alternators that are of a higher amp-rated supply.

If you drive daily, maybe not much; if you sit parked while running loads for an extended time, solar is what keeps the bank up. Most van builds use both.